An apparatus for clearing a traveled surface such as a road, express highway and/or airport runway of snow, slush, water, dust, dirt and the like can comprise a framework in which two rotatable drums are mounted around which is guided a conveyor belt for the cleared material, movable transverse to the direction of travel or inclined in the operating location.
Airfield runways in particular require a complete cleaning of snow and/or slush since otherwise air traffic may be hindered. Besides satisfyingly high cleaning standards, the apparatus for clearing the runway must operate at very high speed since the runway is not available for takeoffs and landings during the cleaning process.
In addition the runways must not only be free of snow and/or slush but also water, dust, dirt or the like to guarantee safe flight operations. Analogous conditions exist for other traveled surfaces such as roads and express highways.
For removal of snow and/or slush found on a traveled surface, particularly a flight runway, an apparatus is known which comprises brush roller rotated in a direction opposite to the travel direction. Using this device the traveled surface can be cleared and cleaned of snow and/or slush. This apparatus is however disadvantageous since the cleared material is whirled by rotation of the brush rollers so that it is again displaced with a lateral velocity component reaching the traveled surface depending on the inclined position of the brush rollers relative to the travel direction.
This means that for cleaning a section of runway whose width depends on the length of the brush rollers and on their inclined position relative to the travel direction, the cleared material must be engaged many times by the brush rollers. Despite intervention of a rejection or deflection device, the cleared material is slung around and is fed in a spiral motion into a region lateral to the operating surface on which the apparatus works. Then a second clearing process is performed using a second clearing device or the same clearing device and the cleared material is engaged again in this second clearing process and displaced laterally a distance about equal to the operating width of the clearing apparatus. This apparatus has, therefore, very poor efficiency as far as clearing a traveled surface goes.
Another disadvantage of this apparatus is that it must be built with very long brush rollers to attain an operating width suitable for these conditions. Thus a very expensive construction is required. As a consequence this apparatus with the brush rollers is provided with a supporting arm which rests on a rotating frame at its front end on the bearing or supporting member of a carrier vehicle like a semitrailer and which is supported at its rear end by an undercarriage by which devices required for the apparatus are supported. Also brush rollers are known which have an undercarriage both at their front and rear ends so that they require a towing vehicle.
In each case, the structural requirements include very expensive longitudinally extending undercarriages in which the brush rollers are mounted and by which the loads occurring in operation are taken, e.g. by pivoting.
This is particularly necessary since in clearing of snow and/or slush, portions of the cleared material can freeze on the brush rollers. Imbalances thereby occur in the rotation which must be overcome by correspondingly heavier supports or bearings and expensive undercarriages. These measures limit the the clearing speed and thus in the operating speed.
In another clearing apparatus, a supporting frame has at least two rotatable drums around on which a conveyor belt for the cleared material is guided movable transverse to the travel direction or inclined to the operating position. In this clearing apparatus the drums are vertical so that the conveyor belt is located in a plane perpendicular or normal to the traveled surface. This known clearing apparatus also does not satisfy the objects of my invention. Therein the conveyor belt cannot be brought into contact with the traveled surface with both the front and the rear stretch simultaneously. Thus forces acting in two different directions could be transmitted by the conveyor belt to the supporting frame. Additionally the cleared material could be fed by the one stretch in a first direction and by the other stretch in the opposite direction.
As a consequence, in this known clearing apparatus the conveyor belt must be kept spaced from the traveled surface. This arrangement has the disadvantage that no complete clearing of the traveled surface can be attained. This is not particularly a disadvantage when the clearing apparatus is used for clearing small quantities of material, e.g. for small quantities of snow or to clear the traveled surface of dust; dirt. In a number of cases, particularly with airport runways, however, a very much more complete clearing of the traveled surface is desired.